1. Field of the Invention
The invention relates to Internet Protocol (IP) communication networks, and more particularly to checking the stability of IP networks.
2. Description of the Prior Art
The person skilled in the art knows that what is usually referred to as the Internet is a set of autonomous systems (AS) interconnected by IP routers and each consisting of one or more IP networks also interconnected by IP routers (also known as gateways).
Each autonomous system is generally under the control of a single Internet operator, in particular from the administrative point of view.
For data packets to be able to reach their destination, they must be routed in accordance with the services defined by service level agreements (SLA) between users who send them and operators. For these agreements to be complied with, the Internet network must have great stability, which is particularly difficult to achieve given that IP networks and the autonomous systems that constitute it change all the time and may malfunction.
To achieve a certain stability, Internet routers must constantly exchange routing information by means of routing protocols such as the Border Gateway Protocol (BGP), version 4 of which is defined by IETF standards RFC 1771 and 1772.
It is also essential to collect operating information within IP networks in order to adapt their functions to changing circumstances and to what is currently required and to verify the consistency of the routing information exchanged. There exist for this purpose routing checking tools, some of which are installed in the IP routers. These tools are in particular capable of determining if routing information contained in routing protocol messages received or to be sent is valid or invalid, that is to say sound or unsound. Now, regardless of the validity of routing information that has been checked one or more times, the routing information is transmitted to the destination peer router(s), without any distinction between information that is valid, invalid or merely unchecked. Invalid (or erroneous) information can therefore propagate through the whole or part of the Internet network, without distinction, compromising its stability.
Thus an object of the invention is to remedy this drawback.